Regeneron Pharmaceuticals Inc. will add 300 jobs to its drug-production operations in East Greenbush, the company and Gov. Andrew Cuomo announced Tuesday night. The expansion builds off early success Regeneron has realized with Eylea, a drug to treat macular degeneration, which leads to blindness. The $70 million investment builds upon expansion plans Regeneron (Nasdaq: REGN) began pursuing with the town starting in the summer, and first reported by The Business Review. Cuomo called it the largest announced biotech expansion in the state this year. Regeneron's plans call for 65,000 square feet of new space for clinical trials and commercialization, as well as new office space. It will be a multi-year expansion that is projected to increase head count by 55 percent, to about 840 people.